The neural code for taste, as recorded from pontine neurons, appears to include a toxicity dimension. This would be an important revelation, as it would serve as the mechanism for the hedonically approprate behavior shown by decerbrate rats and anencephalic human neontes. It would mean that our basic perception of taste and our emotional response to that perception were integrated at brain stem levels. Our conclusion on this matter can only be tentative because our analysis is based on only four taste qualities (5 concentrations of each). Thus it is important to conduct a systematic experiment recording the neural responses to stimuli spanning a range of toxicities while simultaneously collecting behavioral data on the palatability of these stimuli. The palatability dimension will be inversely related to toxicity. In addition, since we now feel that the basic aspects of taste are mediated in the brain stem, we must begin preliminary studies concerning the functional role of forebrain taste sites, especially thalamus. The literature suggests that the thalamus may be involved with integrating gustation with other senses, especially olfaction and somesthesis, or with the internal body state, specifically fluid level and previous intestinal reactions to stimuli. We will vary these parameters, beginning with fluid level, to see how they affect thalamic responses.